During well completion operations it is often desirable to cement a tubular inside another conduit. This other conduit may be a cased well bore or an open hole formation or the like. To ensure optimal efficiency of the cementing process, it is desirable to have the tubular spaced away from the sides of the conduit to permit cement to flow between the tubular and the conduit around the entire circumference of the tubular. This spacing of the tubular with respect to the conduit is achieved using a centraliser.
There are a number of types of conventional centraliser on the market. For example, bow centralisers centralise, as their name suggests, by bowing a piece of metal into engagement with a conduit wall to space a tubular centrally in the conduit. Bow spring centralisers have drawbacks. For example, bow spring centralisers have limited load bearing capacity meaning they can fail to move the tubular into an optimum centralised position with respect to the conduit.
Other centraliser assemblies are provided which have a greater load bearing capacity but are made of many components such as legs, buttons, pistons etc. which are necessary to energise their centralising feature.